[Polly] [Docs] Add a catch-all file to document workflow & tricks.

[bollu]

Summary

• Write about bugpoint and git-svn for now.
• Plan to write a detailed guide on general polly-day-to-day workflow.

[grosser]

Great. This sounds very good!

docs/TipsAndTricks.rst

20 ↗

(On Diff #102329)

instead of "supporting passes" maybe use "opt option flags"

37 ↗

(On Diff #102329)

You can also use 'bugpoint -O3 file.ll -opt-args -polly' to let bugpoint track down the pass that causes a crash.

polly/trunk/docs/TipsAndTricks.rst

+==================================================
+Tips and Tricks on using and contributing to Polly
+==================================================
+
+Commiting to polly trunk
+------------------------
+    - `General reference to git-svn workflow <https://stackoverflow.com/questions/190431/is-git-svn-dcommit-after-merging-in-git-dangerous>`_
+
+
+Using bugpoint to track down errors in large files
+--------------------------------------------------
+
+    If you know the ``opt`` invocation and have a large ``.ll`` file that causes
+    an error, ``bugpoint`` allows one to reduce the size of test cases.
+
+    The general calling pattern is:
+
+    - ``$ bugpoint <file.ll> <pass that causes the crash> -opt-args <opt option flags>``
+
+    An example invocation is:
+
+    - ``$ bugpoint crash.ll -polly-codegen -opt-args  -polly-canonicalize -polly-process-unprofitable``
+
+    For more documentation on bugpoint, `Visit the LLVM manual <http://llvm.org/docs/Bugpoint.html>`_
+
+
+Understanding which pass makes a particular change
+--------------------------------------------------
+
+    If you know that something like `opt -O3 -polly` makes a change, but you wish to
+    isolate which pass makes a change, the steps are as follows:
+
+    - ``$ bugpoint -O3 file.ll -opt-args -polly``  will allow bugpoint to track down the pass which causes the crash.
+
+    To do this manually:
+
+    - ``$ opt -O3 -polly -debug-pass=Arguments`` to get all passes that are run by default. ``-debug-pass=Arguments`` will list all passes that have run.
+    - Bisect down to the pass that changes it.
+

polly/trunk/docs/index.rst

 ===========
 
 .. toctree::
    :maxdepth: 2
 
    Architecture
    UsingPollyWithClang
    HowToManuallyUseTheIndividualPiecesOfPolly
+   TipsAndTricks
 
 * `A list of Polly passes <http://polly.llvm.org/documentation/passes.html>`_
 
 Indices and tables
 ==================
 
 * :ref:`genindex`
 * :ref:`search`